From 88101146f2ec7d53ffb793e365f05097ffd35fd3 Mon Sep 17 00:00:00 2001 From: marha Date: Mon, 18 Jul 2011 10:33:05 +0200 Subject: cvs version of pthreads --- pthreads/pthread_cond_destroy.c | 504 ++++++++++++++++++++-------------------- 1 file changed, 253 insertions(+), 251 deletions(-) (limited to 'pthreads/pthread_cond_destroy.c') diff --git a/pthreads/pthread_cond_destroy.c b/pthreads/pthread_cond_destroy.c index 34550f08d..40d4a0896 100644 --- a/pthreads/pthread_cond_destroy.c +++ b/pthreads/pthread_cond_destroy.c @@ -1,251 +1,253 @@ -/* - * pthread_cond_destroy.c - * - * Description: - * This translation unit implements condition variables and their primitives. - * - * - * -------------------------------------------------------------------------- - * - * Pthreads-win32 - POSIX Threads Library for Win32 - * Copyright(C) 1998 John E. Bossom - * Copyright(C) 1999,2005 Pthreads-win32 contributors - * - * Contact Email: rpj@callisto.canberra.edu.au - * - * The current list of contributors is contained - * in the file CONTRIBUTORS included with the source - * code distribution. The list can also be seen at the - * following World Wide Web location: - * http://sources.redhat.com/pthreads-win32/contributors.html - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library in the file COPYING.LIB; - * if not, write to the Free Software Foundation, Inc., - * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA - */ - -#include "pthread.h" -#include "implement.h" - -int -pthread_cond_destroy (pthread_cond_t * cond) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * This function destroys a condition variable - * - * - * PARAMETERS - * cond - * pointer to an instance of pthread_cond_t - * - * - * DESCRIPTION - * This function destroys a condition variable. - * - * NOTES: - * 1) A condition variable can be destroyed - * immediately after all the threads that - * are blocked on it are awakened. e.g. - * - * struct list { - * pthread_mutex_t lm; - * ... - * } - * - * struct elt { - * key k; - * int busy; - * pthread_cond_t notbusy; - * ... - * } - * - * - * struct elt * - * list_find(struct list *lp, key k) - * { - * struct elt *ep; - * - * pthread_mutex_lock(&lp->lm); - * while ((ep = find_elt(l,k) != NULL) && ep->busy) - * pthread_cond_wait(&ep->notbusy, &lp->lm); - * if (ep != NULL) - * ep->busy = 1; - * pthread_mutex_unlock(&lp->lm); - * return(ep); - * } - * - * delete_elt(struct list *lp, struct elt *ep) - * { - * pthread_mutex_lock(&lp->lm); - * assert(ep->busy); - * ... remove ep from list ... - * ep->busy = 0; - * (A) pthread_cond_broadcast(&ep->notbusy); - * pthread_mutex_unlock(&lp->lm); - * (B) pthread_cond_destroy(&rp->notbusy); - * free(ep); - * } - * - * In this example, the condition variable - * and its list element may be freed (line B) - * immediately after all threads waiting for - * it are awakened (line A), since the mutex - * and the code ensure that no other thread - * can touch the element to be deleted. - * - * RESULTS - * 0 successfully released condition variable, - * EINVAL 'cond' is invalid, - * EBUSY 'cond' is in use, - * - * ------------------------------------------------------ - */ -{ - pthread_cond_t cv; - int result = 0, result1 = 0, result2 = 0; - - /* - * Assuming any race condition here is harmless. - */ - if (cond == NULL || *cond == NULL) - { - return EINVAL; - } - - if (*cond != PTHREAD_COND_INITIALIZER) - { - EnterCriticalSection (&ptw32_cond_list_lock); - - cv = *cond; - - /* - * Close the gate; this will synchronize this thread with - * all already signaled waiters to let them retract their - * waiter status - SEE NOTE 1 ABOVE!!! - */ - if (ptw32_semwait (&(cv->semBlockLock)) != 0) /* Non-cancelable */ - { - result = errno; - } - else - { - /* - * !TRY! lock mtxUnblockLock; try will detect busy condition - * and will not cause a deadlock with respect to concurrent - * signal/broadcast. - */ - if ((result = pthread_mutex_trylock (&(cv->mtxUnblockLock))) != 0) - { - (void) sem_post (&(cv->semBlockLock)); - } - } - - if (result != 0) - { - LeaveCriticalSection (&ptw32_cond_list_lock); - return result; - } - - /* - * Check whether cv is still busy (still has waiters) - */ - if (cv->nWaitersBlocked > cv->nWaitersGone) - { - if (sem_post (&(cv->semBlockLock)) != 0) - { - result = errno; - } - result1 = pthread_mutex_unlock (&(cv->mtxUnblockLock)); - result2 = EBUSY; - } - else - { - /* - * Now it is safe to destroy - */ - *cond = NULL; - - if (sem_destroy (&(cv->semBlockLock)) != 0) - { - result = errno; - } - if (sem_destroy (&(cv->semBlockQueue)) != 0) - { - result1 = errno; - } - if ((result2 = pthread_mutex_unlock (&(cv->mtxUnblockLock))) == 0) - { - result2 = pthread_mutex_destroy (&(cv->mtxUnblockLock)); - } - - /* Unlink the CV from the list */ - - if (ptw32_cond_list_head == cv) - { - ptw32_cond_list_head = cv->next; - } - else - { - cv->prev->next = cv->next; - } - - if (ptw32_cond_list_tail == cv) - { - ptw32_cond_list_tail = cv->prev; - } - else - { - cv->next->prev = cv->prev; - } - - (void) free (cv); - } - - LeaveCriticalSection (&ptw32_cond_list_lock); - } - else - { - /* - * See notes in ptw32_cond_check_need_init() above also. - */ - EnterCriticalSection (&ptw32_cond_test_init_lock); - - /* - * Check again. - */ - if (*cond == PTHREAD_COND_INITIALIZER) - { - /* - * This is all we need to do to destroy a statically - * initialised cond that has not yet been used (initialised). - * If we get to here, another thread waiting to initialise - * this cond will get an EINVAL. That's OK. - */ - *cond = NULL; - } - else - { - /* - * The cv has been initialised while we were waiting - * so assume it's in use. - */ - result = EBUSY; - } - - LeaveCriticalSection (&ptw32_cond_test_init_lock); - } - - return ((result != 0) ? result : ((result1 != 0) ? result1 : result2)); -} +/* + * pthread_cond_destroy.c + * + * Description: + * This translation unit implements condition variables and their primitives. + * + * + * -------------------------------------------------------------------------- + * + * Pthreads-win32 - POSIX Threads Library for Win32 + * Copyright(C) 1998 John E. Bossom + * Copyright(C) 1999,2005 Pthreads-win32 contributors + * + * Contact Email: rpj@callisto.canberra.edu.au + * + * The current list of contributors is contained + * in the file CONTRIBUTORS included with the source + * code distribution. The list can also be seen at the + * following World Wide Web location: + * http://sources.redhat.com/pthreads-win32/contributors.html + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library in the file COPYING.LIB; + * if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#include "pthread.h" +#include "implement.h" + +int +pthread_cond_destroy (pthread_cond_t * cond) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * This function destroys a condition variable + * + * + * PARAMETERS + * cond + * pointer to an instance of pthread_cond_t + * + * + * DESCRIPTION + * This function destroys a condition variable. + * + * NOTES: + * 1) A condition variable can be destroyed + * immediately after all the threads that + * are blocked on it are awakened. e.g. + * + * struct list { + * pthread_mutex_t lm; + * ... + * } + * + * struct elt { + * key k; + * int busy; + * pthread_cond_t notbusy; + * ... + * } + * + * + * struct elt * + * list_find(struct list *lp, key k) + * { + * struct elt *ep; + * + * pthread_mutex_lock(&lp->lm); + * while ((ep = find_elt(l,k) != NULL) && ep->busy) + * pthread_cond_wait(&ep->notbusy, &lp->lm); + * if (ep != NULL) + * ep->busy = 1; + * pthread_mutex_unlock(&lp->lm); + * return(ep); + * } + * + * delete_elt(struct list *lp, struct elt *ep) + * { + * pthread_mutex_lock(&lp->lm); + * assert(ep->busy); + * ... remove ep from list ... + * ep->busy = 0; + * (A) pthread_cond_broadcast(&ep->notbusy); + * pthread_mutex_unlock(&lp->lm); + * (B) pthread_cond_destroy(&rp->notbusy); + * free(ep); + * } + * + * In this example, the condition variable + * and its list element may be freed (line B) + * immediately after all threads waiting for + * it are awakened (line A), since the mutex + * and the code ensure that no other thread + * can touch the element to be deleted. + * + * RESULTS + * 0 successfully released condition variable, + * EINVAL 'cond' is invalid, + * EBUSY 'cond' is in use, + * + * ------------------------------------------------------ + */ +{ + pthread_cond_t cv; + int result = 0, result1 = 0, result2 = 0; + + /* + * Assuming any race condition here is harmless. + */ + if (cond == NULL || *cond == NULL) + { + return EINVAL; + } + + if (*cond != PTHREAD_COND_INITIALIZER) + { + ptw32_mcs_local_node_t node; + ptw32_mcs_lock_acquire(&ptw32_cond_list_lock, &node); + + cv = *cond; + + /* + * Close the gate; this will synchronize this thread with + * all already signaled waiters to let them retract their + * waiter status - SEE NOTE 1 ABOVE!!! + */ + if (ptw32_semwait (&(cv->semBlockLock)) != 0) /* Non-cancelable */ + { + result = errno; + } + else + { + /* + * !TRY! lock mtxUnblockLock; try will detect busy condition + * and will not cause a deadlock with respect to concurrent + * signal/broadcast. + */ + if ((result = pthread_mutex_trylock (&(cv->mtxUnblockLock))) != 0) + { + (void) sem_post (&(cv->semBlockLock)); + } + } + + if (result != 0) + { + ptw32_mcs_lock_release(&node); + return result; + } + + /* + * Check whether cv is still busy (still has waiters) + */ + if (cv->nWaitersBlocked > cv->nWaitersGone) + { + if (sem_post (&(cv->semBlockLock)) != 0) + { + result = errno; + } + result1 = pthread_mutex_unlock (&(cv->mtxUnblockLock)); + result2 = EBUSY; + } + else + { + /* + * Now it is safe to destroy + */ + *cond = NULL; + + if (sem_destroy (&(cv->semBlockLock)) != 0) + { + result = errno; + } + if (sem_destroy (&(cv->semBlockQueue)) != 0) + { + result1 = errno; + } + if ((result2 = pthread_mutex_unlock (&(cv->mtxUnblockLock))) == 0) + { + result2 = pthread_mutex_destroy (&(cv->mtxUnblockLock)); + } + + /* Unlink the CV from the list */ + + if (ptw32_cond_list_head == cv) + { + ptw32_cond_list_head = cv->next; + } + else + { + cv->prev->next = cv->next; + } + + if (ptw32_cond_list_tail == cv) + { + ptw32_cond_list_tail = cv->prev; + } + else + { + cv->next->prev = cv->prev; + } + + (void) free (cv); + } + + ptw32_mcs_lock_release(&node); + } + else + { + ptw32_mcs_local_node_t node; + /* + * See notes in ptw32_cond_check_need_init() above also. + */ + ptw32_mcs_lock_acquire(&ptw32_cond_test_init_lock, &node); + + /* + * Check again. + */ + if (*cond == PTHREAD_COND_INITIALIZER) + { + /* + * This is all we need to do to destroy a statically + * initialised cond that has not yet been used (initialised). + * If we get to here, another thread waiting to initialise + * this cond will get an EINVAL. That's OK. + */ + *cond = NULL; + } + else + { + /* + * The cv has been initialised while we were waiting + * so assume it's in use. + */ + result = EBUSY; + } + + ptw32_mcs_lock_release(&node); + } + + return ((result != 0) ? result : ((result1 != 0) ? result1 : result2)); +} -- cgit v1.2.3